linux-ext4 - Re: [PATCH v2 05/23] fsverity: make fsverity_verify

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Date:   Wed, 5 Apr 2023 17:50:46 +0000
From:   Eric Biggers <ebiggers@...nel.org>
To:     Christoph Hellwig <hch@...radead.org>
Cc:     Andrey Albershteyn <aalbersh@...hat.com>, djwong@...nel.org,
        dchinner@...hat.com, linux-xfs@...r.kernel.org,
        fsverity@...ts.linux.dev, rpeterso@...hat.com, agruenba@...hat.com,
        xiang@...nel.org, chao@...nel.org,
        damien.lemoal@...nsource.wdc.com, jth@...nel.org,
        linux-erofs@...ts.ozlabs.org, linux-btrfs@...r.kernel.org,
        linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
        cluster-devel@...hat.com
Subject: Re: [PATCH v2 05/23] fsverity: make fsverity_verify_folio() accept
 folio's offset and size

On Wed, Apr 05, 2023 at 08:46:45AM -0700, Christoph Hellwig wrote:
> On Wed, Apr 05, 2023 at 12:36:42PM +0200, Andrey Albershteyn wrote:
> > Hi Christoph,
> > 
> > On Tue, Apr 04, 2023 at 08:30:36AM -0700, Christoph Hellwig wrote:
> > > On Tue, Apr 04, 2023 at 04:53:01PM +0200, Andrey Albershteyn wrote:
> > > > Not the whole folio always need to be verified by fs-verity (e.g.
> > > > with 1k blocks). Use passed folio's offset and size.
> > > 
> > > Why can't those callers just call fsverity_verify_blocks directly?
> > > 
> > 
> > They can. Calling _verify_folio with explicit offset; size appeared
> > more clear to me. But I'm ok with dropping this patch to have full
> > folio verify function.
> 
> Well, there is no point in a wrapper if it has the exact same signature
> and functionality as the functionality being wrapped.
> 
> That being said, right now fsverity_verify_folio, so it might make sense
> to either rename it, or rename fsverity_verify_blocks to
> fsverity_verify_folio.  But that's really a question for Eric.

I thought it would be confusing for fsverity_verify_folio() to not actually
verify a whole folio.  So, for now we have:

    fsverity_verify_page: verify a whole page
    fsverity_verify_folio: verify a whole folio
    fsverity_verify_blocks: verify a range of blocks in a folio

IMO that makes sense.  Note: fsverity_verify_folio() is currently unused, but
ext4 might use it.

So, just use fsverity_verify_blocks().

- Eric